As preparation for a cohort study of black and white California Seventh- day Adventists this application seeks funds to perform a series of parallel validation studies in both racial groups. Seventh-day Adventists are a health-conscious religious group who do not smoke cigarettes or drink alcohol by church proscription. A lacto-ovo vegetarian diet is strongly recommended. However, great variation in the adherence to this recommendation results in an increased range of consumption of a wide variety of vegetable foods and fruits, thus increasing statistical power. Hence Adventists are an ideal population in which to investigate diet-cancer associations. Our previous cohort study demonstrated protective associations between consumption of several vegetables and fruits, and a number of different cancers. For colon and bladder cancers, meat consumption appeared hazardous. The future cohort study will extend these observations using a larger population, and an improved, validated questionnaire. The inclusion of black Adventists will be an additional focus. The quality of the two exposure questionnaires, developed separately for black and white Adventists, will be an important determinant of its success. The preparatory studies that we now propose use subjects either selected from the local area, or small random samples from around the state. We will choose 80-120 food frequency questionnaires from an extensive list of possible foods using a stepwise correlational approach and an independent validation of the derived nutrient indices. This latter will use repeated 24-hour recalls as the reference. Several biochemical markers will be measured, and will provide further independent validation of the consumption of selected nutrients and foods. The effect on validity of questions dealing with recipe and prepared dishes will be formally explored. Other substudies will investigate the validity of recalling dietary habits from 17 years previously (possible in whites only) and the reliability of recalling habits from 17 and 33 years previously, for both races. A substudy will document the validity and reliability of different questions on exercise habits in blacks. Such a study is nearing completion for white Adventists. During Year 02, a draft of the final questionnaire will be prepared and after appropriate pretesting, the ability of subjects of both races, old and young, to understand and respond appropriately, will be extensively checked. Finally, the completed and validated questionnaires in final format will be checked for reliability when subjects complete the questionnaires on two occasions 6-8 weeks apart. Several manuscripts describing the results of these studies will be prepared and submitted for publication.